1. Field of the Invention
The present invention relates to an AFM (atomic force microscope) cantilever including a field effect transistor (FET) and a method for manufacturing the same; and, more particularly, to a method for manufacturing an AFM cantilever including an FET formed by a photolithography process, wherein an effective channel length of the FET is a nano-scale.
2. Background of the Related Art
A probe member of an AFM (atomic force microscope) has a sharp shape. Such probe member is formed in a sharp shape by wet etching or dry etching a general semiconductor substrate. The probe member formed through the wet etching becomes a pyramid shape and the prove member formed through a dry etching becomes a cone shape.
However, there is a very difficult problem in a manufacturing process that a conventional MOSFET (metal-oxide semiconductor field effect transistor) type device is mounted on the AFC cantilever.
Therefore, in order to solve such problem, a cantilever of which a FET structure is formed by a micro-machining method is recommended in Korea publication patent publication No. 2001-045981.
In a basic operation of a cantilever to form an FET (field effect transistor) by using a micro-machining method, after the cantilever formed thereon a source and a drain is vertically attached to a sample on which an insulation material is formed, a principle that an amount of current flowing into a drain according to a charge distribution of a sample surface is changed when a voltage is applied to the source is applied.
In Korea patent registration Nos. 0466157, 0466158, 0515734, 0555045 and 0558376, the cantilever is operated by forming a device channel on a sharp probe member, whereas in Korea patent registration No. 0515735, a high aspect-ratio based probe is constructed on the probe member at which a channel is formed.
However, in conventional techniques such as Korea patent registration Nos. 0466157, 0466158, 0515734, 0555045 and 0558376, the FET structure is formed through a process for forming the source/drain and the channel on the sharp probe member formed by a conventional process for manufacturing the AFM cantilever. There are a shortcoming that an error occurs during a process for reducing a width of the channel and a problem that a theoretical simulation cannot be performed for controlling an effective channel.
And also, in Korean patent registration No. 0515735 to form the high aspect ratio based probe on the probe member where the channel is formed, there is a problem that it is difficult to predict an effective length of the channel since a channel formation process is performed after forming the sharp probe member.
That is, since a technique of manufacturing a conventional FET AFM cantilever performs the channel formation process after forming the sharp probe member, the effective length of the channel cannot be measured finally. And also, there exist a problem that a high price electron beam lithography device is required for reducing a process error. In this result, it causes many problems such as reduction of process yield and reliability and an increase of process costs or the like.